Merge branch 'agp-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied...

[karo-tx-linux.git] / drivers / uio / uio.c

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 9ac22c7c385487e212d8c46fbfab56d12fc7c860..5dccf057a7dd41a5f31f69ec4d5d7982615655ec 100644 (file)
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -67,6 +67,11 @@ static ssize_t map_size_show(struct uio_mem *mem, char *buf)
        return sprintf(buf, "0x%lx\n", mem->size);
 }
 
+static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
+{
+       return sprintf(buf, "0x%lx\n", mem->addr & ~PAGE_MASK);
+}
+
 struct uio_sysfs_entry {
        struct attribute attr;
        ssize_t (*show)(struct uio_mem *, char *);
@@ -77,10 +82,13 @@ static struct uio_sysfs_entry addr_attribute =
        __ATTR(addr, S_IRUGO, map_addr_show, NULL);
 static struct uio_sysfs_entry size_attribute =
        __ATTR(size, S_IRUGO, map_size_show, NULL);
+static struct uio_sysfs_entry offset_attribute =
+       __ATTR(offset, S_IRUGO, map_offset_show, NULL);
 
 static struct attribute *attrs[] = {
        &addr_attribute.attr,
        &size_attribute.attr,
+       &offset_attribute.attr,
        NULL,   /* need to NULL terminate the list of attributes */
 };
 
@@ -482,15 +490,23 @@ static int uio_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
        struct uio_device *idev = vma->vm_private_data;
        struct page *page;
+       unsigned long offset;
 
        int mi = uio_find_mem_index(vma);
        if (mi < 0)
                return VM_FAULT_SIGBUS;
 
+       /*
+        * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
+        * to use mem[N].
+        */
+       offset = (vmf->pgoff - mi) << PAGE_SHIFT;
+
        if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
-               page = virt_to_page(idev->info->mem[mi].addr);
+               page = virt_to_page(idev->info->mem[mi].addr + offset);
        else
-               page = vmalloc_to_page((void*)idev->info->mem[mi].addr);
+               page = vmalloc_to_page((void *)idev->info->mem[mi].addr
+                                                       + offset);
        get_page(page);
        vmf->page = page;
        return 0;